1. Field of the Invention
This invention relates to an antenna module which is suited to mobile communications and an electronic device such as a personal computer for executing radio communication.
2. Description of the Related Art
In recent years, portable terminals have been-widely used which are provided with a whip antenna and an internal antenna for communication and also another antenna for radio communication of data between themselves and other electronic devices.
Further, portable mobile electronic devices such as a notebook personal computer which execute radio data communication through wireless LAN have been also widely used. These mobile electronic devices incorporate antennas.
Further, the electronic device such as a portable terminal and a notebook personal computer in recent years are requested to incorporate an antenna for radio communication. However, since the antenna itself is incorporated, it is demanded that the gain and directivity of transmission/reception is assured or improved without influencing the structure/package or appearance of the electronic device.
Further, as regards these electronic devices, their slimming, downsizing and high-density packaging have advanced year after year. Correspondingly, downsizing of an incorporated antenna and in packaging for assuring the gain of the antenna have been also demanded.
In order to fulfill the above demand, a pattern antenna was formed on the rear surface of a box, otherwise the external shape of the box was partially deformed to form the antenna (e.g. JP-A-2002-207535 and JP-A-10-290707).
However, in the case where the pattern antenna is formed on the rear surface of the box, the antenna is greatly upsized so that the space therefor must be ensured. This is a serious problem for the electronic device whose sliming and downsizing is indispensable.
Further, where the pattern antenna or the antenna constructed by a laminated electronic component is placed on a mounting substrate existing on the rear surface of the box or inside thereof, such a problem occurs that a sufficient transmission/reception gain cannot be obtained because of an external box. Particularly, in order to assure both the light weight and strength of the box, as the case may be, the outer wall of the box is made of an Mg alloy. If the outer wall is made of such a metal, it constitutes a shield. Thus, it is difficult to execute the transmission/reception between the internal antenna and the outside.
In the case of the antenna with a projection formed on the outer wall of the box, the appearance is not elegant. Such a antenna is inferior in design, and above all is not comfortable for a user. In addition, such an antenna brings about malfunction or damage.
Further, in such a case, because of the structure of the box or antenna, the gain and directivity of transmission/reception cannot be assured sufficiently.